1. Field of the Invention
The present invention relates to a grinding apparatus for grinding workpieces. More specifically, the present invention relates to a grinding apparatus for remotely grinding workpieces such as metal castings.
2. Information Disclosure Statement
When metal castings are made, such castings include burrs, risers, parting lines or flow offs that make it necessary for an operator to manually grind such flaws from the casting.
Accordingly, a grinder must secure the casting so that such metal casting can be manually ground by means of a rotary grinding wheel or the like.
During the grinding operation, the operator must reorient and secure the workpiece several times in order to gain access to the various facets of the casting. Therefore, the grinding operation becomes a labor intensive step in the manufacture of a machined end product.
Additionally, during the grinding operation, a considerable amount of powdered metal is generated in the vicinity of the grinding process and such dust which becomes ferric oxide presents a considerable health hazard to the grinder and other personnel working in the grinding shop.
Furthermore, because some of the castings weigh up to 600 lb., many grinder operators suffer from back problems and Carpal Tunnel Syndrome and other heath problems. Consequently, it is not unusual for a grinding shop to have a workforce having an average employment stay of less than six months.
Therefore, due to the rapid employment turnover of grinding personnel, the quality of the resultant ground casting is often less than desired.
The present invention overcomes all of the aforementioned problems associated with the prior art arrangements by providing a machine which permits loading of a workpiece and rotation of the workpiece to a grinding location where the workpiece can be remotely manipulated during the grinding process by an operator operating remote control grinding equipment.
Therefore, it is a primary objective of the present invention to provide an apparatus which overcomes the aforementioned problems associated with the prior manual grinding operations and which makes a considerable contribution to the art of grinding castings.
Also, an object of the present invention is the control of dust generated by the grinding operation.
Another objective of the present invention is the provision of an apparatus for grinding castings to a premachining standard.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description of a preferred embodiment of the present invention contained hereinafter taken in conjunction with the annexed drawings.
The present invention relates to an apparatus and method for grinding workpieces. The apparatus includes a frame and a holder rotatably secured to the frame for releasably holding a first workpiece of the workpieces.
Means for rotating the holder from a loading station to a grinding station and grinding means movably secured to the frame and selectively positionable relative to the first workpiece when the first workpiece is located at the grinding station.
Control means for selectively positioning the grinding means relative to the first workpiece for grinding the first workpiece and a further holder rigidly secured to and spaced relative to the holder. The arrangement is such that when the holder is rotated in a direction towards the grinding station, the further holder is rotated in a direction towards the loading station for loading a second workpiece of the workpieces at the loading station so that sequential grinding and loading of the workpieces is permitted.
In a more specific embodiment of the present invention the frame includes a base and a vertical support extending upwardly from the base.
A housing is rotatably supported relative to the vertical support such that the housing rotates about a vertical axis for permitting movement of the workpieces between the loading and the grinding stations.
The frame also includes a first and a second sidewall extending upwardly from the base and a grinder support extending between the sidewalls for supporting the grinding means.
Additionally, the frame includes a cab rigidly secured to the base.
The holder extends radially outwards from the housing, the holder including a first arm rotatably connected to the housing such that the first arm rotates about a horizontal axis.
Also, the first arm has a proximal end adjacent to the housing and a distal end.
A second arm is extendably connected to the first arm, the second arm having a first end which slidably cooperates with the proximal end of the first arm. A second end of the second arm cooperates with the distal end of the first arm such that when the arms are located at the grinding station, the first workpiece is held between the distal end of the first arm and the second end of the second arm so that the accommodation of different size workpieces is permitted and rotation of the first workpiece about the horizontal axis is permitted.
The first arm also includes an anchor rotatably secured to the distal end thereof.
Furthermore, the second arm includes a further anchor rotatably secured to the second end thereof.
A drive means is drivingly connected to at least one of the anchors such that when the first workpiece is disposed between the anchors with the first workpiece being held between the arms, rotation of the first workpiece about a further axis extending between the anchors is permitted.
More particularly, the drive means is drivingly connected to at least one of the anchors such that when the first workpiece is disposed between the anchors with the first workpiece being held between the arms, rotation of the first workpiece about a further axis extending between the anchors is permitted when the first workpiece is disposed in both the grinding and the loading station. The arrangement is such that controlled movement of the first workpiece about a combination of the vertical, horizontal and further axes is permitted, so that accurate location of the first workpiece relative to the grinding means is readily attained.
The means for rotating the holder includes a motor and a drive transmission connected to the motor for driving the housing about the vertical axis.
The grinding means also includes a depending arm supported by the grinder support.
The grinder support includes a first and a second transverse rail, each rail extending between the sidewalls.
A carriage is supported and guided by the rails such that movement of the carriage between the sidewalls is permitted.
A screw and block mechanism is mounted on the carriage such that the block supports the depending arm for permitting movement of the depending arm in a first direction between the sidewalls and in a second direction normal to the first direction.
Lifting means is connected to the depending arm for permitting vertical movement of the depending arm relative to the carriage so that movement of the depending arm to any location is permitted.
The grinding means is rotatably secured to the depending arm.
The control means includes electronic circuits for controlling both the movement and positioning of the workpieces disposed at the loading and grinding stations and movement of the grinding means relative to the first workpiece at the grinding station.
In an alternative embodiment of the present invention, the control means includes hydraulic servo circuits for controlling both the movement and positioning of the workpieces disposed at the loading and grinding stations and movement of the grinding means relative to the first workpiece at the grinding station.
In a preferred embodiment of the present invention, the further holder is disposed diametrically opposite to the holder, the arrangement being such that in operation of the apparatus, a first operator receives and loads the first workpiece onto the further holder. The first workpiece is rotated to the grinding station and subsequently, a second operator remotely controls both the orientation of the first workpiece and remotely adjusts the position of the grinding means relative to the first workpiece for carrying out a grinding operation thereon. Such grinding operation is performed while the first operator loads the second workpiece at the loading station.
On completion of the grinding operation, the first workpiece is rotated to the loading station where the first operator inspects, hand grinds if necessary and unloads the first workpiece while the second workpiece is being ground remotely by the second operator.
Preferably, the cab further includes an air conditioning system.
Many modifications and variations of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description of a preferred embodiment of the present invention contained hereinafter taken in conjunction with the annexed drawings. However, such modifications and variations fall within the spirit and scope of the present invention as defined by the appended claims.